Representative images of PrP
deposition in the midbrain of tg338 mice after challenge with scrapie. The deposition patterns observed were characteristic of strains G338
(a), Apl338ii (b) and Cag338
(c). Three mice showed phenotypic characteristics typical of both G338 and Apl338ii patterns; photos d-f are all from a single mouse showing small discrete aggregates (d, red arrow) in the habenular bodies which is a G338 characteristic feature in addition to plaques and large aggregates in subpial areas (d, black arrow; e, periaqueductal grey matter; f, lateral ventricle) which are associated with Apl338ii. In a single mouse with Apl338ii phenotype, punctate and prominent intraneuronal labelling (g) which are features associated with the P338 pattern were also observed; the Apl338ii phenotype is not usually associated with intraneuronal labelling (h). The neurons in g and h are located in the olive nucleus. Scale bar in a-c represents 250 μm; d–f 100 μm; g and h 25 μm.